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    <p>The observer and observable:</p> <p>The idea basically is that you have some class observing another and when something happens the class that is being observed, the Observable, will notify the class that Observes, the Observer, and tell it something has changed. The Observable has methods setChanged() and notifyObservers() to accomplish that. And the Observer listens to that call with the implemented update() method.</p> <p>I put everything into one class so you can copy/paste and run this. When you hit a key you will see how it works.</p> <pre><code>//the textfield is wrapped in a class so that it can extends Observable public class MyTextField extends Observable { private JTextField jTextField = new JTextField(); //this method notifies the observers you will add public void notify(Object o) { this.setChanged(); this.notifyObservers(o); } public JTextField getJTextField() { return jTextField; } } import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import java.util.Observable; import java.util.Observer; import javax.swing.JFrame; import javax.swing.JTextField; import javax.swing.SwingUtilities; // The main class that observes the swing component you tell it to public class Controller implements Observer { private final JFrame jFrame = new JFrame(); private final MyTextField myTextField = new MyTextField(); public Controller() { jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jFrame.pack(); jFrame.setVisible(true); jFrame.add(myTextField.getJTextField()); //here we add the Observer (Controller) to myTextField (Observable) myTextField.addObserver(this); //and the keylistener myTextField.getJTextField().addKeyListener(new KeyListener() { @Override public void keyTyped(KeyEvent e) { System.out.println("keyTyped " + e.getKeyCode()); //now we notify our observers for real myTextField.notify(e.getKeyCode()); } @Override public void keyReleased(KeyEvent e) { System.out.println("keyReleased " + e.getKeyCode()); myTextField.notify(e.getKeyCode()); } @Override public void keyPressed(KeyEvent e) { System.out.println("keyPressed " + e.getKeyCode()); myTextField.notify(e.getKeyCode()); } }); } // this is where the event is received by the Observer // from the observable. @Override public void update(Observable observable, Object object) { System.out.println("Notified by " + observable + " with object " + object); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { new Controller(); } }); } } </code></pre> <p>I hope that is understandable and a solution to your problem :)</p>
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    1. COThis is a really good example that I can understand and I will try implementing (in a while though, no time right now). I got a little confused in one point though. Does the whole JFrame need to be observed or only the JTextField? Because if I have to observe only the textfield this will take me a while modifying probably! Thanks a lot anyway!
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    2. COAnd how can I implement mulitple observers based on different inputs?
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    3. COUnless you have something you want to observe in the JFrame like an onclose/onminimize/... event or something like that, there is no need for it. You can make different instances MyTextField and make them (which is observable) with one or different observers. When you notifyObservers() it will notify all observers you added to the instance of MyTextField.
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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

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